Projectile weapons may include weapons such as bows and slingshots, but this article focusses mainly on sharp weapons which are thrown by hand.
To outline the differences in technique I will differentiate between straight projectile weapons, which include the Chinese throwing knife, needles, quills, the Japanese kunai and the bo shuriken on the one hand- and on the other- spinning weapons, which mainly consist of the Japanese shaken or throwing star, but it van also include playing cards and coins.
Straight throwing weapons:
Incidentally, many of these weapons make good stabbing weapons as well. Because the sharp tip is the only point of contact the aim of the throwing technique is to have the tip penetrate into the target.
The most effective way to accomplish that is to keep the grip on the weapon very loose during the throwing movement and to guide the weapon by supporting it with the thumb or index finger of the throwing hand. The weapon is then propelled by centrifugal force and nothing else. The longer the distance to be thrown the more speed and centrifugal force will be necessary to prevent the weapon from rotating while in flight. This technique also forms the basis of the Shaolin "Needle through Glass" as well as Ninjutsu's shuriken jutsu.
Most important to get out of the way is that it is not the objective to have the weapon pinned into the target.
The technique used to launch these weapons require less effort and more speed as these weapons are mainly used to instantly create an opening in the heat of battle. In may cases a casual flick of the wrist should be enough. When in flight, the weapon is to spin at the speed of a buzz saw blade. :)
Multiple projectiles can also be flung in rapid succession after enough practice.
The flick can be developed by practising with dumbbell discs.
The above applies to throwing stars, coins, cards or any type of disc that may be available.
A weapon I have not dealt with, but which deserves mention is the Indian Chakram. Anyone with knowledge about the use of this weapon is welcome to make a contribution to this blog by emailing me at email@example.com.